This collection has a very nice gradient style to them. Be warned, all files are PSD file which means you can only alter them in Photoshop. Each file contains (3) different versions: Rounded Edges, Square, Rounded Sides. All you simply need to do is color the layer you want and you have beautiful looking buttons. Also, the font used was "Trebuchet MS."
There is a sample JPG of all the buttons inside the ZIP. Enjoy!